Microcystis aeruginosa is the most common species responsible for toxic cyanobacterial blooms and is considered a significant contributor to the production of cyanotoxins, particularly the potent liver toxins called microcystins. Numerous studies investigating Microcystis spp. blooms have revealed their deleterious effects in freshwater environments. However, the available knowledge regarding the global phosphoproteomics of M. aeruginosa and their regulatory roles in toxin generation is limited. In this study, we conducted comparative phosphoproteomic profiling of non-toxic and toxin-producing strains of M. aeruginosa. We identified 59 phosphorylation sites in 37 proteins in a non-toxic strain and 26 phosphorylation sites in 18 proteins in a toxin-producing strain. The analysis of protein phosphorylation abundances and functions in redox homeostasis, energy metabolism, light absorption and photosynthesis showed marked differences between the non-toxic and toxin-producing strains of M. aeruginosa, indicating that these processes are strongly related to toxin generation. Moreover, the protein-protein interaction results indicated that BJ0JVG8 can directly interact with the PemK-like toxin protein B0JQN8. Thus, the phosphorylation of B0JQN8 appears to be associated with the regulatory roles of toxins in physiological activity.

The South-to-North Water Diversion Project (SNWDP) is the largest water transfer project in the world, and its purpose is to relax water constraints in a region facing severe water scarcity. Bacterial communities from these reservoirs are important to human health, and analyzing their diversity and structure is crucial to water safety. Here, we investigated the dynamics of bacterial communities and their relationship with environmental parameters in the terminal reservoir (Miyun Reservoir) of the Middle Route of the SNWDP by high-throughput sequencing technology. Our results showed that Firmicutes, Proteobacteria, Cyanobacteria and Bacterioidetes were the most abundant phyla in the water column, and the community composition fluctuated seasonally. Moreover, the detected diversity of the bacterial community composition provided novel insights into the ongoing biogeochemical processes. The temperature was positively correlated with the dominant bacteria, with other factors, including the total dissolved solids, total phosphorus, dissolved oxygen and total nitrogen, shaping the structure and distribution of the microbial community. Furthermore, the metagenome showed broad phylogenetic diversity, indicating that organisms were involved in multiple essential environmental processes. This work is important for building a database to understand how microbial communities change after water transfers.

The rapid expansion of global aquaculture has led to wastewater enriched with nitrogen, phosphorus, organic matter, antibiotics, and heavy metals, posing serious risks such as eutrophication, ecological imbalance, and public health threats. Conventional physical, chemical, and biological treatments face limitations including high cost, secondary pollution, and insufficient efficiency, limiting sustainable wastewater management. Algal–bacterial symbiotic systems (ABSS) provide a sustainable alternative, coupling the metabolic complementarity of microalgae and bacteria for effective pollutant mitigation and concurrent biomass valorization. Immobilizing microbial consortia within carrier materials enhances system stability, tolerance to environmental changes, and scalability. This review systematically summarizes the pollution characteristics and ecological risks of aquaculture effluents, highlighting the limitations of conventional treatment methods. It focuses on the metabolic cooperation within ABSS, including nutrient cycling and pollutant degradation, the impact of environmental factors, and the role of immobilization carriers in enhancing system performance and biomass resource valorization. Despite their potential, ABSS still face challenges related to mass transfer limitations, complex microbial interactions, and difficulties in scale-up. Future research should focus on improving environmental adaptability, regulating microbial dynamics, designing intelligent and cost-effective carriers, and developing modular engineering systems to enable robust and scalable solutions for sustainable aquaculture wastewater treatment.

Industrial recirculating aquaculture systems (RAS) constitute an energy-saving and environmentally friendly approach to modern aquaculture production. The hydrodynamic characteristics within these systems, coupled with the ecological environment of the fish, are essential for the efficient operation of the system and for promoting optimal fish growth and welfare. These systems provide several advantages, such as high intensification, efficient water resource utilization, enhanced environmental control, and minimal environmental pollution. Consequently, it has emerged as prominent avenue for advancing aquaculture development in China. This paper begins with an examination of the fundamental concepts and primary tank structures underpinning industrial RAS. It then proceeds to elucidate the hydrodynamic characteristics within RAS and their interrelationship with fish growth and welfare. Furthermore, it offers a thorough review of tank hydrodynamic characteristics and fish interactions from various perspectives, including operational parameters, hydrodynamic drive equipment, fish behavior, and the aquaculture environment. Finally, the limitations of current studies are assessed, and potential future research directions are proposed.

The rapid expansion of large-scale aquaculture has created a demand for more efficient and sustainable farming systems. Among these, land-based circular tank aquaculture is emerging as a key solution due to its high efficiency, scalability, and effective waste management capabilities. Optimizing the hydrodynamic characteristics of these tanks is crucial for improving water quality management and ensuring the health of cultured fish. This study investigates the hydrodynamic characteristics of large land-based circular tanks, focusing on the effects of water pusher configurations and the presence of fish on flow dynamics and sewage collection efficiency. Field experiments were conducted under two conditions: with and without fish, while varying the pusher diameter, deployment angles, and the number of pushers. The flow characteristics at different layers of the tanks were measured using Acoustic Doppler Velocimetry. The results indicate that the pusher deployment has a more significant impact on the flow field and hydrodynamic characteristics compared with the pusher diameter. The optimal configuration for water circulation and sewage collection was identified when the pusher diameter was 11 cm, the deployment angle was 45°, and the number of pushers was 6. The presence of fish significantly influenced the flow field distribution by expanding high velocity flow zones. The findings provide a theoretical basis for optimizing water pusher deployment in large-scale circular tanks with fish, thereby contributing to improved water quality management and fish health.

Optimizing hydrodynamic performance and dissolved oxygen (DO) distribution is essential for improving water quality management in industrial recirculating aquaculture systems. This study combines experimental measurements and data analysis to evaluate the effects of the inlet pipe flow rate (Q), deployment distance ratio (d/r), deployment angle (θ), inlet pipe structure on hydrodynamics and the dissolved oxygen distribution across various tank layers. The flow field distribution in the tanks was measured using Acoustic Doppler Velocimetry (ADV), and the hydrodynamic characteristics, including average velocity (v_avg) and the velocity uniformity coefficient (DU₅₀), were quantitatively analyzed. The dissolved oxygen content at different tank layers was recorded using an Aquameter GPS portable multi-parameter water quality analyzer. The findings indicate that average velocity (v_avg) and the velocity uniformity coefficient (DU₅₀) are key determinants of the hydrodynamic characteristic of circular aquaculture tanks. Optimal hydrodynamic performance occurs for the vertical single-pipe porous configuration at Q = 9 L/s, d/r = 1/4, and θ = 45°,the average velocity reached 0.0669 m/s, and the uniformity coefficients attained a maximum value of 40.4282. In a vertical single-pipe porous structure, the tank exhibits higher dissolved oxygen levels compared to a horizontal single-pipe single-hole structure. Under identical water inflow rates and deployment distance ratios, dissolved oxygen levels in the surface layer of the circular aquaculture tank are significantly greater than that in the bottom layer. The results of this study provide valuable insights for optimizing the engineering design of industrial circular aquaculture tanks and addressing the dissolved oxygen distribution across different water layers.